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論文
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ISMAILOV, Murad ; DURST, Franz ; OBOKATA, Tomio
概要:
application/pdf<br />Journal Article<br />In the present study an LDA-based technique was applied to analyze details of
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a transient pipe-flow induced upstream by a fuel ingector. Due to highly accurate measurements of the instantaneous time series of velocity, fuel flow rate and pressure gradient were achieved. The pipe flow has been driven under an injection pressure of 0.6MPa at high injection frequencies of 25 and 50 Hz. The influence of the outflow orifice diameter, varid in range from 100 to 500 μm, on the transient pipe flow dynamics has also been described. The results show that transient behavior of rapid oscillating pipe flow is remarkably and systematically dependent on injection frequency and duration as well as on the orifice diameter.
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| 2.
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論文
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ISMAILOV, Murad ; ISHIMA, Tsuneaki ; OBOKATA, Tomio ; TSUKAGOSHI, Masayoshi ; KOBAYASHI, Kazumitsu
概要:
application/pdf<br />Journal Article<br />Time-dependent centerline velocity is measured using LDA-flow meter. Swirl inj
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ector at frequencies of 22 and 46 Hz generates oscillated flow under high-pressure from 4 up to 7 MPa. The encoded time-series of velocity is used to reconstruct the time-variable series of instantaneous flow rate and pressure gradient. Transient injection dynamics are analyzed to obtain basec characteristics of an injection system that will be able to be used for real time monitoring or active controlling of high-pressure gasoline injectors. The results obtained through analyzing the integrated mass rates within a cycle, indicate that a certain injection system is characterized by the flow rate constant γ which independent on injection duration and can be obtained from only accurate measurement of centerline velocity in the fuel transport pipeline. The present technique allows us to simplify the injection model and can be effectively adopted for practical employment on active and passive control with respect to gasoline direct injection engines.
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| 3.
論文 |
論文
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ISMAILOV, Murad ; ISHIMA, Tsuneaki ; OBOKATA, Tomio ; TSUKAGOSHI, Masayoshi ; KOBAYASHI, Kazumitsu
概要:
application/pdf<br />Journal Article<br />A high-pressure swirl type spray has been experimentally analyzed by using a phase Doppler anemometer(PDA). The experiment was performed with an injection pressure of 5 MPa and an injection
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frequency of about 46 Hz. The PDA data was obtained in a two-dimensional plane and arranged with the injection phase angle. The arranged data of mean velocity, Sauter mean diameter, and droplet number density were visualized by using commercial software. In this paper, the data were compared with the results of visualization. It is indicated by the experiment that the large velocity and large size droplets initiated from the injector with small spray angle at the beginning of the valve opening duration. This stage was called core jet. In the next stage called quasi umbrella spray, the spray developed with large spray angle. After closing the valve, the spray remains increasing its velocity and diameter. This was caused by the "post injection". Using PDA, the detailed feature of the spray can be discussed with high temporal resolution.
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| 4.
論文 |
論文
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ISMAILOV, Murad ; ISHIMA, Tsuneaki ; TAKEDA, Chikashi ; OBOKATA, Tomio ; TSUKAGOSHI, Masayoshi ; KOBAYASHI, Kazumitsu
概要:
application/pdf<br />Journal Article<br />Transient temporal and spatial spray characteristics have been investigated. A
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kind of practical fuel injector with swirl nozzle was examined under variable injection duration within the range of 0.25 to 4.0 ms and injection pressure 5.0 and 7.0 MPa. The fuel spray was injected at a cycling frequency of 50 Hz in a room under normal atmospheric condition. Considered details of sub-millisecond transient dynamics were observed by using a high-speed video camera with temporal resolution of 24.69 μs(40500 frames / s). The results indicate that investigated spray consists of two incorporated flow fractions that are a core jet and a quasi-umbrella droplets spray simultaneously moving down and swirling in local cross-axis domains. Instantaneous transient values of axial and radial penetration were accurately evaluated and analyzed. It was observed that after actual injection a post-injection of fuel droplets occurs and the time-delay and lifetime of these droplets were systematically estimated.
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